Field of the Invention
The present invention relates to a folding device in a corrugated cardboard box making machine. In FIGS. 1 and 2, there is shown a fundamental structure of the corrugated cardboard box making machine. FIG. 1 shows a series of states how a corrugated cardboard sheet S fed to a folding unit section of the corrugated cardboard box making machine is formed into a corrugated cardboard box S'.
The corrugated cardboard sheet S supplied to a slotter section A of the corrugated cardboard making machine is slotted and creasing lines are formed thereon. Then, both side portions of the sheet S forwarded to the folding unit section B is folded at a right angle, and thereafter, it is flatly folded to form a corrugated cardboard box S'. The cardboard box S' is then transported into a discharge section C.
In a preceding process B1 at the folding unit section B, the corrugated cardboard sheet S is folded along the creasing lines p--p and q--q. A state showing how the sheet S is folded is shown by II and III in the FIG. 1.
In FIG. 6, there is shown a conventional structure whereby the sheet S is folded. In the FIG. 6, a reference numeral 33 designates a belt supporting member which supports a folding belt 1 and a transport belt 10. A reference numeral 32 represents a screw shaft which moves the belt supporting member 33 in the axial direction of the shaft 32 and is supported by frame 18. A reference numeral 31 designates a motor provided for rotatively driving the screw shaft 32. Accordingly, when the motor 31 is rotated, the folding belt 1 and the transport belt 10 are moved in the axial direction of the shaft 32 to be positioned at a suitable position for folding work of the sheet S.
A reference numeral 8 represents a guide supporting member on which an upper guide 5 is attached. A reference numeral 38 designates a screw shaft for moving the guide supporting member 8 in the axial direction of the shaft 32 and is supported by the frame 18. A reference numeral 37 designates a chain transmission mechanism for transmitting the rotation of the screw shaft 32 to the screw shaft 38. Both of the shafts 32 and 38 are simultaneously rotated in the same rotational frequency.
A reference numeral 51 represents a regulating means for finely regulating a position of the guide supporting member 8 in the axial direction of the shaft 32. The regulating means 51 is similar to a regulating means 53 illustrated in FIG. 7 which will be described below, and therefore, description on the regulating means 51 is omitted.
When the motor 31 is rotated, the rotatory power of the motor is transmitted to the screw shaft 32, the chain transmission mechanism 37, and the screw shaft 38 subsequently in this order to move the guide supporting member 8 in the axial direction of the shaft 32. The upper guide 5 is positioned at a standard position suitable for folding the sheet S.
As illustrated in the FIG. 6, the corrugated cardboard sheet S is folded by the folding belt 1 and the upper guide 5, and at a final stage of the process B1, both side portions of the sheet S are folded at a right angle.
There are various sizes of corrugated cardboard boxes that are manufactured by the corrugated cardboard box making machine. Accordingly, the positions of creasing lines by which the sheets S are folded vary according to the sizes and kinds of the boxes to be manufactured. It is, therefore, arranged to position the folding belt 1 and the upper guide 5 at a suitable position by simultaneously moving them with rotation of the motor 31 as described above in order to adapt for the manufacture of various kinds of corrugated cardboard boxes.
Corrugated cardboard sheets S vary in thickness, and therefore, it is necessary to adjust a space between the folding belt 1 and the upper guide 5 to adapt for the thickness of a corrugated cardboard sheet S. The regulating means 51 is therefore provided to independently move the guide supporting member 8 for making the space a most suitable value.
In the succeeding process B2 at the folding unit section B, the folded portions at both sides of the sheet S are inwardly pressed from both sides and the sheet S is flatly folded down. The flatly folded state is illustrated by IV and V in the FIG. 1.
In FIG. 7, there is shown a conventional structure whereby a corrugated cardboard sheet S is folded and a sheet folding width is rectified. In the FIG. 7, reference numerals 10 and 1 represent a transport belt and a folding belt respectively. The folding belt 1 changes the posture of its angle of inclination from the vertical posture as shown in the FIG. 6 to the horizontal posture as shown in the FIG. 7 by gradual inclination. With this action, the sheet S is caught in a space between the folding belt 1 and the transport belt 10, and the sheet S is folded down along the creasing lines p--p, q--q.
A reference numeral 15 represents a gauge belt supporting member and a gauge belt 11 is supported thereat through a roller 14. The gauge belt supporting member 15 moves simultaneously with the belt supporting member 33 (refer to FIG. 6) for the same amount of distance in the axial direction of the shaft 32. There is arranged a regulating means 53 for finely regulating the position of the gauge belt supporting member 15 relative to the belt supporting member 33. The regulating means 53 is provided with a screw shaft 44, and a handle 43 is attached to one end of the screw shaft 44.
A reference numeral 49 designates a nut to which a pointer 48 is fixed, and the nut 49 is also screwed in the screw shaft 44. A reference numeral 47 represents a scale which is fixed on the belt supporting member 33. When the handle 43 is rotated by an operator, the gauge belt 11 and the pointer 48 are moved simultaneously, and the operator is able to position the gauge belt 11 to a position most suitable for the folding width of the sheet S by watching graduations on the scale 47 to which the pointer 48 indicates.
The gauge belt 11 is provided to rectify a folding width by pressing the folding sections of the sheet S from both sides. A required folding width of the corrugated cardboard box S' varies, and therefore, it is arranged to rectify the position of the gauge belt 11 in accordance with a folding requirement.
In the prior art described above, there exists the following problems.
A first problem is that the working efficiency is lowered when a set of boxes being processed is changed to another set of boxes thereby worsening the working ratio of the corrugated cardboard box making machine which will be described more in detail as follows.
Because of market diversification in recent years, the requirement for manufacturing varieties of boxes in small quantity per lot with delivery in a short period of time is strongly called for from the manufacturers of corrugated cardboard boxes. In order to comply with this requirement, it is required to quickly and frequently perform operations of changing over a set of boxes being processed to another set of boxes. In the prior art, rough positioning of the folding belt 1, transport belt 10, upper guide 5, and gauge belt 11 can be quickly conducted. However, the operation for regulating a space between the folding belt 1 and the upper guide 5, and the operation for regulating a position of the gauge belt 11 are being conducted manually by operator. Moreover, this requires the operator to position the upper guide 5 and gauge belt 11 by operating the handle, carefully watching graduations to which the pointer 48 on the scale 47 indicates. Such operations are complicated and take a long period of time.
In the corrugated cardboard box making machine, when a set of boxes being conducted is changed over to another set of boxes, a printing plate exchange operation and an ink changing operation are conducted in the printing unit section, and in the slotter unit section, an operation for changing the positions of slotting blades is carried out. Further, in the folding unit section, it is required to move the upper guide 5, gauge belt 11 and the like in the axial direction of the shaft 32. When a set of boxes being processed is changed over to another set of boxes, it will be more advantageous if other operations are carried out at the same time while the exchange operations of printing plate and ink changing operations are automatically conducted which generally takes a long period of time. However, among said operations, it takes a long time for positioning and regulating the positions of the upper guide 5 and gauge belt 11 by operating the handle, and even after the exchange operation of printing plate and ink changing operation are completed, it sometimes happens that the regulating and positioning operations are not finished. As a result, it takes a long period of time for changing over a set of boxes and the working ratio of the machine is lowered.
A second problem is that accuracy for manufacturing boxes is not stabilized, and consequently, it lowers the quality of boxes and badly affects a packing process which will now be described more concretely below.
The positioning and regulating operations of the upper guide 5 and gauge belt 11 are manually conducted and it is required to perform the operations in a short period of time. It is, therefore, difficult to accurately conduct the operations. Consequently, irregularity in the outcome of the operations occur, and the positions of the upper guide 5 and gauge belt 11 are made inaccurate. In this case, the accuracy in the folding width of folded corrugated cardboard boxes is worsened.
The next process for a packing operation is generally automated. If, therefore, corrugated cardboard boxes of inaccurate folding width are forwarded to a packing machine, there arise such problems as follows.
When the folding width of the corrugated cardboard boxes is wider than a standard width, claws of the packing machine can not get into a gap between a packing case, which packs the folded corrugated cardboard boxes, and the corrugated cardboard boxes since the gap becomes smaller, and the packing operation can not be carried out. On the other hand, when the folding width of the corrugated cardboard boxes is narrower than the standard width, a bigger gap is made between the packing case which packs the folded corrugated cardboard boxes and the corrugated cardboard boxes, and dust easily gets into the gap.